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Color Order FAQ

 

 

Do you have a question about color? Here is our current list of Frequently Asked Questions.

This page has been populated with questions submitted from around the world over the last decade. While we are no longer accepting new questions, we hope you enjoy reading the questions and answers here.

Other categories can be selected below:
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I use the Munsell Color Books to develop color harmonies for clients to use on short term projects. Is there an inexpensive way to get swatches or chips that match the Munsell notation? Can I print them?   (answer)

Scientifically speaking, is black a color? Is white a color?   (answer)

Is there a formula for calculating Delta E in Munsell?   (answer)

Is there still a copyright on the Munsell color system? If so, who owns it?   (answer)

Are you aware of any software packages or even just charts, that list Munsell colors by both code and name?   (answer)

I would like to come up with a color scheme that assigns an absolute color value to common color words. In this scheme I would want scarlet to have a distinct and absolute value different than crimson or puce. Is there any site or program that has assigned absolute color values to the English names of colors?   (answer)

How do you find a RAL equivalent of an NCS colour reference?   (answer)

What is the RAL number for PMS 268 plum? I've attempted to find a cross-reference tool and have not been successful!   (answer)

Could you please tell me, what color would 1.2Y 6/11 be?   (answer)

At what illuminant temperature are Munsell neutrals (N6, N7, etc.) designed to be neutral?   (answer)

Is it proper to state a Munsell notation for a metallic or pearlescent color, or is Munsell a solid color only notation system?   (answer)

Is there any source of spectral reflectance data for samples in the Munsell Book of Color?   (answer)

Does the Munsell system account for the Helmholtz-Kohlrausch effect?   (answer)

How closely do the Munsell Renotation data reflect the actual tristimulus values of samples in the Munsell Book of Color as viewed under Standard Illuminant C?   (answer)

What's a good reference for information on the Munsell system?   (answer)

Please give an example of how to begin with a tertiary color,subtract one color and then subtract another color but don't end up with a primary color.   (answer)

How precise areMunsell color charts meant to be read?   (answer)

Could you possibly tell me the formulas for the harmonic equivalents (tones) of red, orange, yellow, green, blue, violet?   (answer)

Can you provide me with a formula for RGB values given Munsell coordinates?   (answer)

Could you please tell me the equivalent Federal No. (Std 595) for Munsell No. 2.1 YR 5.6/16 (Orange)?   (answer)

How can I convert NCS color mode to RGB mode in Photoshop?   (answer)

How do I assign a RAL number to a standard color used by my company?   (answer)

Is there a specific color that could be called Munsell green? What is its Munsell designation? I understand this color is commonly used at places like university campuses for exterior electrical equipment enclosures.   (answer)

What is an easy way to create a color scheme using an elliptical path and a Munsell conversion program?   (answer)

As an Interior Design student I know that paint manufacturers, geologists, anthropologists, and color designers use the Munsell system of color notation. What other industries currently his system to code their color? Automobile industry? Textile Industry?   (answer)

Do you have a table of NCS color code corresponding to RAL color code?   (answer)

What does RAL stand for?   (answer)

Is there a simple formula to take numbers obtained by matching paint samples to the 1929 Munsell book and convert them to the numbers that would be obtained using the current Munsell book?   (answer)

I need a color swatch for 10YR 9/1, do you have this?   (answer)

When refering to "pure" colors (red, green, blue, orange) what is the corresponding notation in the Munsell system?   (answer)

Which of these Munsell soil designations is the reddest: 5R 6/4, 5R 5/2, 5R 7/3, 5R 6/3?   (answer)

Is there a concordance listing the ISCC-NBS color name for each chip in the Munsell Book of Color?   (answer)

Where can I purchase a "student model" Munsell Color Tree?   (answer)

Could you help me convert the Munsell codes to RAL codes?   (answer)

Why are there chromaticity values of zero or less than zero in the Munsell data on the MCSL web site?   (answer)

Can the Munsell 7GY3.29/1.5 Green be converted into a ANSI number?   (answer)

I'm a wood scientist. Can you help me convert values from NCS to CIELAB?   (answer)

I have a Munsell paint specification of 7GY3.29/1.5. My paints use IF numbers. Can you help me transform this request to an IF number?   (answer)

I am trying to find a precise, systematic way to describe the colors of inks and metals used in medieval manuscripts. For example, I want to be able to define "red" as a range of similar colors and "scarlet" as a different range.   (answer)

Can you help me to discriminate between color space, color model, and color system? I'm confused!   (answer)

How many colors does Munsell solid establish?   (answer)

I have read that a digital darkroom should be painted Munsell 8 gray. What should I tell my paint dealer so he can mix a color close to this?   (answer)

I have a paint is specified as Munsell colors and I need the RGB equivalents to display on my computer. Can you tell me the RGB for 1BG 6.3/1.4 and 4.6G 9.0/0.5?   (answer)

How precise are Munsell color sample meant to be read?   (answer)

Why was Munsell's colour system the most widely and globally accepted one?   (answer)

What is the Pantone equivalent to color RAL 3020?   (answer)

How can I transfer from Munsell notation to a single number indicator of overall color?   (answer)

What are the general norms for pale & pastel colours?Which are the colours (generic names) are considered as pale & pastel colours?   (answer)

The freeware from gretagmacbeth.com cannot convert RGB values less than (34,34,34), the software tells me that the values are "Out of Munsell Range". Does Munsell support no color below (34,34,34)?   (answer)

Are you aware of an algorithm in the public domain for calculation of NCS notation from reflectance spectra?   (answer)

How do I get the value of Munsell renotation coordinates?   (answer)

I am a geologist working with Munsell colour chips and need to know how accurate and precise manufactured chips are and how long they can be expected to last (i.e. before fading).   (answer)

Please explain to me what the Munsell Color Disc and Munsell Charts are. The discs used are: red (5 R 2.6/13), yellow (2.5 YR 5/12), black (N1), grey (N4). I need to measure the color of tomato paste by this method.   (answer)

Can you tell me the RAL Number which is most closely match with Munsell N9.5?   (answer)

Why is yellow the lightest color of the spectrum?   (answer)

How do I create a value Intensity scale illustrating three dimensions of colour? Could you define a cool and warm colour and whats a colour scheme? Could you give me examples of complementary, split-complementary colors?   (answer)

Did Munsell ever design and make public an eight-hue color circle? If not, such false facts are circulating on the internet. For example, see mauigateway.   (answer)

I have a reflectance spectrum of a soil sample. Can you help me convert this reflectance to CIE X,Y,Z and then to Munsell HVC?   (answer)

Can you help me convert from a Munsell color specification to a RAL color specification?   (answer)

I am developing a visual program to pick color harmonies of a color based on RGB values. Are there equations that could help me determine color harmonies?   (answer)

Why might the published measurements for Munsell neutral scale differ? For example, the reflectance values for the 1929 "Munsell Book of Color" are different in the 1933 Munsell et al article as compared to the 1940 Glenn article.   (answer)




I use the Munsell Color Books to develop color harmonies for clients to use on short term projects. Is there an inexpensive way to get swatches or chips that match the Munsell notation? Can I print them? (883)
You can get authentic Munsell chips from X-Rite (they sell all Munsell products), but they are not particularly inexpensive. It would be difficult to print them accurately. I would suggest using some inexpensive samples such as the Coloraid papers and then using your Munsell books to visually determine a Munsell designation for the various samples. That would probably be the most cost effective method. (Back to top)


Scientifically speaking, is black a color? Is white a color? (862)
There is no question that black and white are colors.

The technical definition of color that is internationally agreed upon includes them as colors and, specifically, there is a definition of achromatic colors as follows: "A color lacking hue; white or grey or black". (Back to top)


Is there a formula for calculating Delta E in Munsell? (850)
This person answered their own question before I got to it, but It seems worth pointing out the Nickerson Index of Fading on our FAQ. Here's what she wrote...

"Hello Dr. Fairchild,
   : I've submitted another questions to your wonderful "Ask a Color Scientist" page, but I thought I would also send a note to you on the same topic, but with a bit more detail.
   : I am looking for an easy color difference formula for Munsell. I know that it won't be as spot-on accurate as the advanced formulas used with more modern color spaces, but that's OK, I want something that is generally reliable, and that will be good enough.
   : I've done a bit of Googling on this and the only thing that I have found is the 1936 Nickerson "Index of Fading" formula:
   : ΔE = 2/5CΔH + 6ΔV + 3ΔC

Where H/V/C are Munsell coordinates. (Back to top)


Is there still a copyright on the Munsell color system? If so, who owns it? (845)
X-Rite currently produces and sells Munsell products. The colorimetric coordinates of the colors have been published, so the colors themselves are not copyrighted. However, it is likely that X-Rite does have the various products protected by copyright. It would be best to check with X-Rite. (Back to top)


Are you aware of any software packages or even just charts, that list Munsell colors by both code and name? (842)
I can't vouch for the the completeness or accuracy, but I have found an online table of the ISCC-NBS color naming system with Munsell designations. It might be helpful for you. (Back to top)


I would like to come up with a color scheme that assigns an absolute color value to common color words. In this scheme I would want scarlet to have a distinct and absolute value different than crimson or puce. Is there any site or program that has assigned absolute color values to the English names of colors? (833)
For this purpose, I would highly recommend the "ISCC-NBS Dictionary of Color Names". It is well out of print, but used copies can still be found online and in libraries. It provides Munsell designations for a wide collection of common color names. However, you should be aware that color names are very imprecise and there is a range of designations for each name. It is quite likely that scarlet and crimson will have some overlap. (Back to top)


How do you find a RAL equivalent of an NCS colour reference? (816)
The RAL system is proprietary, so it is not easily possible to convert to/from RAL from/to any other system. That is even true with one that has been published, like NCS. The best I can recommend is to purchase the RAL swatches and visually match to the desired NCS color (you could also do the matching instrumentally). (Back to top)


What is the RAL number for PMS 268 plum? I've attempted to find a cross-reference tool and have not been successful! (786)
Both RAL and Pantone PMS systems are proprietary. They make their money on selling the samples that embody their systems (or software to do conversions like you are looking for). They are both protective of their systems in order to retain their market. That is why you cannot find a conversion tool and also why I can't help you. (Back to top)


Could you please tell me, what color would 1.2Y 6/11 be? (776)
Since it is a Munsell designation, which is a published color system, I can. Munsell also has the advantage that you can estimate the color appearance directly from the notation. This color would be a slightly greenish yellow that is fairly light and very saturated. This link includes a nice explanation of the Munsell system. (Back to top)


At what illuminant temperature are Munsell neutrals (N6, N7, etc.) designed to be neutral? (726)
The Munsell samples are specifically designed to be viewed under CIE illuminant C (simulated daylight with a correlated color temperature of about 6774K). However the actually samples are quite spectrally nonselective (i.e., flat spectral reflectance curves) and should appear neutral under a variety of white light sources. (Back to top)


Is it proper to state a Munsell notation for a metallic or pearlescent color, or is Munsell a solid color only notation system? (715)
It can be done, but it should be done with great care. With metallic or pearlescent materials, the color changes with changes in illumination and view angles. Thus, if you wanted to use Munsell notations for such materials, they too would have to change with illumination and view angle and the material would have quite a large number of Munsell notations. (Back to top)


Is there any source of spectral reflectance data for samples in the Munsell Book of Color? (713)
I don't know of any and the reflectances are not uniquely defined, so different books might have difference reflectance properties (while still having the colorimetry of the renotation). (Back to top)


Does the Munsell system account for the Helmholtz-Kohlrausch effect? (712)
No. The Helmholtz-Kohlrausch effect is an anomaly in the Munsell system. A gray at value 5 will look darker than a high-chroma color at value 5. At some point in the process of defining the Munsell system and renotation, it was decided that value would be directly related to luminance and that created this issue. It is best to think of the Munsell hue, value, and chroma scales as three independent scales, rather than as a three-dimensional space to avoid this issue. In other words ... only compare value when hue and chroma are constant, etc. (Back to top)


How closely do the Munsell Renotation data reflect the actual tristimulus values of samples in the Munsell Book of Color as viewed under Standard Illuminant C? (711)
The Munsell samples are made to very tight tolerances with respect to the Munsell renotation data. There is some indication of this accuracy level mentioned in the Munsell books themselves. (Back to top)


What's a good reference for information on the Munsell system? (706)
I'd suggest this article from American Scientist to get an introduction to Munsell and his system along with references to more details. (Back to top)


Please give an example of how to begin with a tertiary color,subtract one color and then subtract another color but don't end up with a primary color. (701)
Well, it depends on how you define "tertiary color". There are a few definitions out there. If you define it as a mixture of 3 primaries, then removing two of them will always leave you with a primary. I've also seen definitions that consist of mixing two secondary colors or mixing a secondary with an adjacent primary. So it really all depends on how you define "tertiary" and how you define the "colors" you are removing. It also would depend on how the colors are being mixed.

Looking at the most common definition, a tertiary only has two primary colors in it, so if you remove all of one, and then all of the other, you are left with either black (additive mixing) or white (subtractive mixing) and that would answer your question. (Back to top)


How precise areMunsell color charts meant to be read? (696)
One step in Munsell Chroma is approximately 5 CIELAB units (very approximately). In general , people accept that approximately 1.0 CIELAB unit is a visual threshold (again very approximately and dependent on the color in question). Thus, observers should be able to fairly reliably discriminate about 0.2 Munsell Chroma steps under the best of viewing conditions. So what are the best of viewing conditions? A nice bright daylight booth with fairly large samples set up right next to each other.

Now, I've seen a few of the Munsell soil books, and generally they are ... "soiled". I would be very surprised if the samples in the real world could be considered precise to much better than one Chroma step. On top of that you need to factor in the varying lighting and observers. Certainly with all those variables there is no way the judgements can be considered precise to 0.1 Chroma step. Your "opposing viewpoint" is the one that makes sense to me as a color scientist. It is certainly in line with what I would expect if I was doing the judgements. (Back to top)


Could you possibly tell me the formulas for the harmonic equivalents (tones) of red, orange, yellow, green, blue, violet? (679)
To my knowledge, there is no scientifically valid link between color and pitch. However a lot of mythology and non-scientific theories exist. You might choose one of the relationships described on this web page. harmonics.com. (Back to top)


Can you provide me with a formula for RGB values given Munsell coordinates? (658)
Actually, I can't. First of all, RGB is not defined and depends on the monitor, operating system, etc. Even if you had calibrated RGB, there are still no formulas to convert to/from Munsell. A lookup table is required. GretagMacbeth provides some conversion freeware and you might also look at the tools at easyrgb.com to get some approximations. (Back to top)


Could you please tell me the equivalent Federal No. (Std 595) for Munsell No. 2.1 YR 5.6/16 (Orange)? (646)
I don't know of a conversion table, so I really can't ... but looking at this page, the only orange that is close is FS 32473. You can buy the FED-STD-695 fan deck at chassis-plans.com and make a visual match to a Munsell book. Again, looking at that page (and my Munsell book) I would say that the only one that is close is FS 32473. (Back to top)


How can I convert NCS color mode to RGB mode in Photoshop? (645)
The NCS system is not defined by any equations that could be used to directly relate it to RGB (or other color specifications). The conversion would have to be made via look-up table. NCS provides some products and software that might help. See ncscolor.com. (Back to top)


How do I assign a RAL number to a standard color used by my company? (624)
RAL is a proprietary color naming system. You would have to find out from them how to set a designation. See ral.de. (Back to top)


Is there a specific color that could be called Munsell green? What is its Munsell designation? I understand this color is commonly used at places like university campuses for exterior electrical equipment enclosures. (609)
I understand why you are perplexed. There is no single color known as "Munsell Green". There is a principal Munsell hue called green that would have the hue designation of 5G. However, even when narrowed down to that single hue, you have many colors because you can still vary value (lightness) and chroma. You would need a designation of all three to have a specific color. (Back to top)


What is an easy way to create a color scheme using an elliptical path and a Munsell conversion program? (574)
I assume you mean an elliptical path through the color space to select the colors in your scheme. An easy way would be to draw (either by hand or electronically) the polar coordinates of the Munsell system and then select the range of hues, etc you want to traverse and simply sketch out the path. There is no need to have a precise ellipse. You can then select the Munsell notation that your path crosses and use the conversion program to convert those over to RGB, CMYK, or whatever other coordinates you would prefer to work in. (Back to top)


As an Interior Design student I know that paint manufacturers, geologists, anthropologists, and color designers use the Munsell system of color notation. What other industries currently his system to code their color? Automobile industry? Textile Industry? (566)
I think you covered most of them. The system is also used in imaging (color reproduction) to help test and improve imaging systems. You might look at this paper I recently co-authored on Munsell and the system for American Scientist. (Back to top)


Do you have a table of NCS color code corresponding to RAL color code? (540)
No, to my knowledge there are no published conversions to/from RAL. On their website, RAL recommends buying all the other systems and doing visual comparisons. (Back to top)


What does RAL stand for? (539)
According to their website:

"In 1925, the private sector and the German government of that time founded the "Reichs-Ausschuss f�r Lieferbedingungen" - RAL - (Committee of the German Reich for Terms and Conditions of Sale)." (Back to top)


Is there a simple formula to take numbers obtained by matching paint samples to the 1929 Munsell book and convert them to the numbers that would be obtained using the current Munsell book? (525)
There is not a simple relationship. The Munsell renotation experiments published in the Journal of the Optical Society of America in the 1940s included the revised (current) designations, but not a relationship back to the 1929 book.

(While not a formula or simple relationship, there is a list of corresponding notations that could be used to build a look-up table in the JOSA 1943 final renotation report.) (Back to top)


I need a color swatch for 10YR 9/1, do you have this? (522)
We don't sell/provide Munsell products, but GretagMacbeth does. Please see this web page. (Back to top)


When refering to "pure" colors (red, green, blue, orange) what is the corresponding notation in the Munsell system? (491)
Here is a description of the Munsell hue scale directly quoted from Fairchild's book, "Color Appearance Models, 2nd Ed.".

"The hue circle in the Munsell system is divided into five principle hues (purple, blue, green, yellow, and red, denoted 5P, 5B, 5G, 5Y, and 5R, respectively) and is designed to divide the complete hue circle into equal perceptual intervals. Five intermediate hues are also designated in the Munsell system as 5PB, 5BG, 5GY, 5YR, and 5RP for a total of 10 hue names. For each of the ten hues there are ten integral hues with notations as illustrated by the range between 5PB and 5P, which is 6PB, 7PB, 8PB, 9PB, 10PB, 1P, 2P, 3P, and 4P. This type of sequence continues around the entire hue circle resulting in 100 integer hue designations that are intended to be equal perceived hue intervals. Hues intermediate to the integer designations are denoted with decimal values (e.g., 7.5PB)." (Back to top)


Which of these Munsell soil designations is the reddest: 5R 6/4, 5R 5/2, 5R 7/3, 5R 6/3? (488)
They are all the same hue, 5R, which is pretty close to a unique red. The second number is value, or lightness, and again they are about the same ranging from a middle lightness of 5 (half way perceptually between white and black) to slightly lighter at 7. The key number is the third one, chroma. A chroma of zero is a neutral gray and as the number increases the sample becomes more colorful. A chroma of 4 is significantly more colorful (more red in this case) than a chroma of 2. So, I would say that your 5R 6/4 sample is the reddest. (Back to top)


Is there a concordance listing the ISCC-NBS color name for each chip in the Munsell Book of Color? (442)
"The ISCC-NBS Method of Designating Colors and a Dictionary of Color Names" provides charts that allow one to look up the ISCC-NBS for any Munsell designation and then to look up synonymous color names. The book is out of print, but can often still be found in used bookstores or on the internet at places like bookfinder.com. (Back to top)


Where can I purchase a "student model" Munsell Color Tree? (426)
I am not aware of a student model of the Munsell Tree, but you might contact GretagMacbeth, the company that sells Munsell products to inquire. There is another product called "The New Munsell Student Color Set" that includes a number of hue pages, but not in the form of the 3D Munsell tree. It is a very useful and helpful resource and might be what you are looking for. It is published by Fairchild Books (no relation) and can be found here. (Back to top)


Could you help me convert the Munsell codes to RAL codes? (415)
I'm afraid not. We do not have the capability to convert from any color system into RAL codes and it is not clear that any utilities for the conversion exist. GretagMacbeth does provide free software for conversion between Munsell and other common color systems. (Back to top)


Why are there chromaticity values of zero or less than zero in the Munsell data on the MCSL web site? (405)
There are such values in the file all.dat. As explained on the Munsell renotation data page, this will contains unreal colors. That is, colors whose chromaticity coordinates lie outside the Macadam limits. One such color: 2.5PB 0.2/20 is shown at the lower end of the red line in the diagram below. The unreal colors are only useful if you want to interpolate color that lie very close to the Macadam Limits. Note that for this very dark color, value=0.2, the spectrum locus is essentially the same locus as the Macadam Limits at this value.
(Back to top)


Can the Munsell 7GY3.29/1.5 Green be converted into a ANSI number? (398)
There are a set of ANSI colors that are defined in terms of Munsell notation (with standards sold by GretagMacbeth. However it appears that each ANSI number is simply a name with a Munsell designation and there would be no way to go in the opposite direction for a conversion (unless one happened to match up perfectly). (Back to top)


I'm a wood scientist. Can you help me convert values from NCS to CIELAB? (383)
I am not aware of any publicly available conversion utilities. NCS does sell software for the conversion ncscolour.com, but it is rather expensive. There have been some papers written on the topic (e.g., N.S. Smith, "A Colour Conversion Program Revisted", Color Research and Application 17, 405-409 (1992).) that might get you started to learn about what has been done. I'm sorry I can't give you a better answer. (Back to top)


I have a Munsell paint specification of 7GY3.29/1.5. My paints use IF numbers. Can you help me transform this request to an IF number? (381)
I'm sorry to say that I am not familiar with the "IF" paint designations that you mentioned and I couldn't find any information on them. I can tell you that the Munsell designation is for a fairly dark color. A middle gray has Value 5 and black has Value 0. The desired color at Value 3.29 would look fairly dark, but not black. It is also low in Chroma. A Chroma of 1.5 is very nearly gray. So you are looking for a green that is fairly dark and close to gray. That might be enough to help you decide which of your two candidates is closer. (Back to top)


I am trying to find a precise, systematic way to describe the colors of inks and metals used in medieval manuscripts. For example, I want to be able to define "red" as a range of similar colors and "scarlet" as a different range. (371)
I would recommend that you refer to the ISCC-NBS Dictionary of Color Names for a systematic technique to relate color specifications (in that case Munsell) to more commonly used color names. You can find a little information on it hare www.colorsystem.com. Unfortunately it is out of print, but you might be able to find a copy in the library and their appear to be some more online resources that might help if you do a Google search for it. (Back to top)


Can you help me to discriminate between color space, color model, and color system? I'm confused! (370)
Your confusion probably arises from the fact that these terms are often used interchangeably.

According to the International Lighting Vocabulary, where such terms are defined, a color space is a manifold of three dimensions for the geometrical representation of color. That might not seem very helpful, but in general a color space is some mathematical representation of colors aligned in a geometrical (usually 3D) spatial structure. I would then add that color models or color systems (terms which are not in the International Lighting Vocabulary) would be names of specific color spaces. For example, the Munsell System defines a particular color space, the CIELAB system another color space, and so on. It is probably safe to say that "model" could be used interchangeably with "system" in this context although some might limit the use "model" to an actual 3D construction of the space with colored samples (as in the actual Munsell Book of Color). I would also note that it might be possible to have a color model, or color system, that describes color in some way other than using a space. For example a color system might just give names to color or values to indendent dimensions of color appearance with no intention of representing them as a 3D space.

For a lot more information and history on this topic, you might want to look at Kuehni's book, "Color Space and Its Divisions: Color Order from Antiquity to the Present". (Back to top)


How many colors does Munsell solid establish? (362)
The Munsell Book of Color is an embodiment of the Munsell system with approximately 1500 color samples. However, that is a limit of the pigments available and the sampling chosen. The Munsell system is not limited to any specific number of colors. It's definition extends well beyond that typically represented with painted samples and the intervals can be subdivided as finely as one likes. (Back to top)


I have read that a digital darkroom should be painted Munsell 8 gray. What should I tell my paint dealer so he can mix a color close to this? (349)
You could just tell him "light gray" or look at their color cards and select the one you are trying to match. That would probably be good enough given the variation in lighting and geometry in any given room. However, if you want to be more precise and accurate, you could tell him to match the CIELAB values of L* = 80, a*=0 and b*=0. I would think they can do that with their color matching system (or they could measure some of their gray color cards to find the closest one). Another alternative would be to purchase a sample of Munsell N8 from GretagMacbeth and then take that in to be matched. (Back to top)


I have a paint is specified as Munsell colors and I need the RGB equivalents to display on my computer. Can you tell me the RGB for 1BG 6.3/1.4 and 4.6G 9.0/0.5? (348)
There is freeware available from GretagMacbeth can perform this conversion. (Back to top)


How precise are Munsell color sample meant to be read? (337)
One step in Munsell Chroma is approximately 5 CIELAB units (very approximately). In general , people accept that approximately 1.0 CIELAB unit is a visual threshold (again very approximately and dependent on the color in question). Thus, observers should be able to fairly reliably discriminate about 0.2 Munsell Chroma steps under the best of viewing conditions. So what are the best of viewing conditions? A nice bright daylight booth with fairly large samples set up right next to each other.

Now, I've seen a few of the Munsell soil books, and generally they are ... "soiled." I would be very surprised if the samples in the real world could be considered precise to much better than one Chroma step. On top of that you need to factor in the varying lighting and observers. Certainly with all those variables there is no way the judgements can be considered precise to 0.1 Chroma step. (Back to top)


Why was Munsell's colour system the most widely and globally accepted one? (332)
It is difficult to say exactly why, but it is probably due to its systematic nature, the perceptual uniformity of the three perceptual dimensions, the degree to which it has been studied and refined over the past decade, and the commercial success of the Munsell Color Company. Part of this is that the system was not only well specified theoretically, but in practice. The samples have always been accurately produced and are very stable over time. (Back to top)


What is the Pantone equivalent to color RAL 3020? (321)
I cannot give you an answer. First of all the Pantone system is proprietary and not related to colorimetry. Second the RAL designation you gave is also a simple index and not related to colorimetry. Some RAL designations are directly related to CIELAB coordinates, but even with such an RAL designation, it would be impossible to convert to Pantone numbers without their proprietary look-up tables (or licensed software that includes them). Your best bet is to inquire with Pantone on how to do this conversion. (Back to top)


How can I transfer from Munsell notation to a single number indicator of overall color? (308)
Color, by its nature, is not uni-dimensional and cannot be expressed in a single number. The Munsell designations show this by expressing color in terms of three dimensions, hue, value(lightness), and chroma. For example, one of your designations was 2.5GY 5/4. The hue is 2.5GY (a greenish-yellow), the value is 5 (a lightness midway perceptually between black and white), and its chroma is 4 (indicating that it is significantly different from gray, chroma=0, but still not too saturated). Perhaps one of those single dimensions would suit your purpose (like chroma, if you are interested in how much color is present), but you can't describe the overall color with just one number, it takes all three. The website coloracademy.co.uk provides some overview on the Munsell system. It can also be found in introductory texts on colorimetry like Berns' Principles of Color Technology 3rd Ed. (Back to top)


What are the general norms for pale & pastel colours?Which are the colours (generic names) are considered as pale & pastel colours? (306)
There are not specific scientific definitions for pale and pastel colors. In common usage the two words are considered synonyms and this is consistent with their use in color naming. Of the basic color terms, none are exclusively pale, or pastel, colors. Instead, pastels would be colors of any hue that are light and near neutral. You might also look at the Colorcurve and Munsell systems, which both define sets of pastel colors. (Back to top)


The freeware from gretagmacbeth.com cannot convert RGB values less than (34,34,34), the software tells me that the values are "Out of Munsell Range". Does Munsell support no color below (34,34,34)? (304)
I am not familiar with the inner workings of the GretagMacbeth freeware, but it is reasonable to make a couple of assumptions. The first would be that they are using the sRGB model for RGB values and the second would be that they are limiting the conversion to Munsell samples that are physically realizable. The RGB code values of (34,34,34) in sRGB correspond approximately to a neutral with a reflectance of 1%. That is a very dark black and impossible to produce as a hard-copy (painted paper in the case of Munsell) sample in the standard Munsell viewing conditions (not a flare-free environment). Thus, it does make sense to me that code values below (34,34,34) are outside the range of the Munsell system. I would simply suggest calling anything that dark essentially Munsell Value 0. (Back to top)


Are you aware of an algorithm in the public domain for calculation of NCS notation from reflectance spectra? (301)
I am not aware of a specific algorithm. There are products available from NCS Colour to do the conversion ncscolour.com, but they are not inexpensive, nor in the public domain. There are conversions and explanations at the EasyRGB site easyrgb.com that might help you. One possibility is to purchase the relatively inexpensive Munsell-NCS conversion data from NCS and then use the free XYZ-Munsell conversion software from GretagMacbeth gretagmacbeth.com to get to Munsell and implement the second conversion yourself. Sorry I can't be more helpful. Let us know if you find something. (Back to top)


How do I get the value of Munsell renotation coordinates? (297)
The Munsell renotation data are available here. One can obtain the values by spectrophotometric measurement of CIE XYZ or CIELAB values followed by lookup in the tables. GretagMacbeth also provides freeware for this conversion. Alternatively, Munsell designations can be obtained by visual matching between a stimulus and reference samples in the Munsell Book of Color. (Back to top)


I am a geologist working with Munsell colour chips and need to know how accurate and precise manufactured chips are and how long they can be expected to last (i.e. before fading). (295)
The specific tolerances on chips in the Munsell system are generally very tight with the books being both accurate and precise. However, I do not know the exact tolerances. Perhaps and inquiry with the current manufacturer, GretagMacbeth , would produce an answer. This web article discusses accuracy and precision of Munsell soil charts. It suggests there could be significant variation from book to book, but this could be due to mistreatment in the field. It also quotes the Munsell company as saying the books are only good for 4 years. Again, this is assuming field use. The Munsell chips are made from very stable materials and should last several decades if stored carefully in the dark when not in use. Our lab has 1929 Munsell books that still appear quite accurate and colorful. (Back to top)


Please explain to me what the Munsell Color Disc and Munsell Charts are. The discs used are: red (5 R 2.6/13), yellow (2.5 YR 5/12), black (N1), grey (N4). I need to measure the color of tomato paste by this method. (294)
Judging from your description you are referring to a form of a disk colorimeter using Munsell papers for the primaries. A disk colorimeter consists of a circle made up of segments of different papers (in this case 4, red, yellow, black, and gray) that can be adjusted to cover different fractions of the circle. The disk is then spun at a rate fast enough to produce temporal fusion of the colored segments (i.e., they all blur together into one color). By adjusting the fractions of the disk made up of each color, the resulting color mixture can be changed to match the tomato past in question. The color designation of the tomato paste would then simply be the fractional areas of each of the four primary colors.

This technique was often used by Albert H. Munsell in the creation of the Munsell system. The disk colorimeters are also sometimes called Maxwell's spinning disks. Some images and more explanation can be found on this web page www.handprint.com. (Back to top)


Can you tell me the RAL Number which is most closely match with Munsell N9.5? (287)
Munsell N9.5 would be a very highly reflecting white paint that will probably be hard to obtain. It would have an L* value of approximately 95, a chroma, C*, of 0, and an undefined hue (since it is neutral). I am not sure how hue is handled in RAL, but I would suspect the RAL designation for this white would be 0,95,0. (Back to top)


Why is yellow the lightest color of the spectrum? (282)
The short answer is, it's not.

Your question could be interpreted many ways. That answer is technically correct, but there are other ways to look at it. If you just took spectral lights and looked at them one wavelength (essentially hue) at a time and had equal amounts of each, then the brightest would be a green wavelength around 555nm. If you look at objects like artists paints, then a saturated yellow color often looks lighter than a saturated green (or other hue). This has several reasons. Mainly is that the yellow will be reflecting more light than the green (often green, yellow and red light to produce a yellow). However, whether or not it looks lighter will depend on the particular pigments being used and the lighting conditions. It might also depend on the observer.

For further study, I would recommend a book on color order systems. You might look at some of the books on the Munsell System, or a book like "Color Space and Its Divisions" by Keuhni for a more detailed treatment. (Back to top)


How do I create a value Intensity scale illustrating three dimensions of colour? Could you define a cool and warm colour and whats a colour scheme? Could you give me examples of complementary, split-complementary colors? (264)
The terms you are asking about are commonly used in color theory for artists. I am not terribly familiar with how they are all used and they are often used in inconsistent and imprecise ways. I would suggest you find a good book on color theory for artists and review that. Probably you should find two books and compare the definitions. Also, these websites seem to have some insight painting.about.com, and www.sanford-artedventures.com.

I'll try to provide some insight on your three questions from a scientific viewpoint. (1) Value and intensity both refer to the light-dark dimension of color, so it doesn't make sense to use those terms in conjunction with three dimensions. You could create value or intensity scales for any colors and fill a three dimensional space showing how any given color varies from light to dark. The Munsell Book of Color provides a nice example of this. (2) Cool generally refers to colors that are more bluish or greenish, while warm refers to colors that are more reddish or yellowish. As far as I know color schemes are just sets of colors that "work well together" for a given application. (3) These refer to relationships of various hues that are part of the color theory mentioned above. Monochromatic would refer to a range of colors of a single hue and achromatic refers to neutrals (from black, through grays, to white). (Back to top)


Did Munsell ever design and make public an eight-hue color circle? If not, such false facts are circulating on the internet. For example, see mauigateway. (262)
I looked at the website you referenced and it mentions the system developed by Munsell in 1905. This is when Munsell first published the "Atlas of the Munsell Colors", which has evolved into the current "Munsell Book of Color". Munsell designated 5 principle hues (red, yellow, green, blue, and purple) and 5 intermediate hues to complete the hue circle. Each of these 10 hues then had 10 subdivisions resulting in the 100 hues in the Munsell system. Thus, you might call the Munsell system a 5-hue circle, a 10-hue circle, or a 100-hue circle (probably the best answer), but it certainly is not an 8-hue circle and never was. I am not aware of Munsell having ever developed an 8-hue system. That reference, as well as most of the other information on the website you referenced, is erroneous.

The website attempts to describe a "true" hue circle. The "trueness" of a hue circle depends on the objective for its use and the type of materials that are being mixed to produce the colors. There is little value in the website other than for mixing the specific transparent colorants mentioned by the artist. The color names on the circles are completely arbitrary. (Back to top)


I have a reflectance spectrum of a soil sample. Can you help me convert this reflectance to CIE X,Y,Z and then to Munsell HVC? (247)
First, note that this answer is not specific to soil samples, and will generally work for any reflectance values.

The basic computation is to multiply your sample reflectance by the spectral power distribution of an illuminant (I would recommend CIE illuminants C or D65, average daylight, since you are interested in Munsell designations) and each of the three CIE 1931 color matching functions (x-bar, y-bar, and z-bar). You then sum these products across the spectrum and multiply each by 100 divided by the sum of y-bar times the illuminant. This gives you relative XYZ tristimulus values. The only way to convert to Munsell designations is to use a look-up table since the Munsell notations are not related to CIE tristimulus values by simple mathematical formulae. Fortunately, GretagMacbeth provides free software for this part of the conversion. For a reference on the calculation of CIE tristiumulus values, XYZ, I would recommend Roy Berns' text, Principles of Color Technology, 3rd Ed. If you are interested in software to perform the computation, there is a book by Westland entitled "Computational Colour Science" that provides some example MATLAB code. Westland's website includes a description of the book, some FAQs that address similar questions, and downloadable code. (Back to top)


Can you help me convert from a Munsell color specification to a RAL color specification? (245)
Thanks for your inquiry. I am personally not that familiar with the RAL specification, but I found these links: paintcenter.org/rj/oct04hh.cfm, and paintcenter.org/rj/apr05a.cfm that suggest that one type of RAL designation is directly related to CIELAB specifications expressed in terms of h,L*,C* (in that order). There is free software from GretagMacbeth to convert between Munsell and CIELAB designations. It appears that you only need to convert the L*a*b* values from the GretagMacbeth program to L*C*h (a rectangular to cylindrical coordinate conversion that can be found in any book on colorimetry) and then round them to integers to convert to RAL specifications. (Back to top)


I am developing a visual program to pick color harmonies of a color based on RGB values. Are there equations that could help me determine color harmonies? (244)
Color harmonies typically are not specified in rigorous mathematical terms, but rather through general rules based on color appearance. There are also a number of theories and techniques for color harmony that make it difficult to specify equations. However, there are colorimetric spaces, and approximations thereof, that do a good job of predicting color appearance and one of these would be a good basis for deriving color harmony computations. The most accurate and complex would be to use the CIECAM02 color appearance model. However, that is probably more complex than warranted for this question. As a simpler approach, I would suggest transforming the RGB values into a simple HVC (hue-value-chroma) or HLS (hue-lightness-saturation) space as is often done in computer graphics. You could then define your color harmonies in that space. There is a lot of information on the internet on color harmonies. This page gives some general overview of the concepts. This one provides computations of harmonious colors for various RGBs, but doesn't specify how "harmony" is computed. It does, however, give code examples for transformations between various color spaces (like RGB to HVC). Lastly, several places mentioned this book as a good reference and there are several other links on that amazon.com page. (Back to top)


Why might the published measurements for Munsell neutral scale differ? For example, the reflectance values for the 1929 "Munsell Book of Color" are different in the 1933 Munsell et al article as compared to the 1940 Glenn article. (241)
I took a look at the two sets of numbers and I cannot come up with a definite answer. Historically, reflectance values were measured relative to smoked magnesium oxide which has a reflectance factor of about 0.98. That would make an older reported value of 1.0 (or 100%) map to a modern measured value of 0.98 (or 98%). That was my first thought for your data, however, the two sets don't differ by a constant factor and the discrepancy is in the wrong direction for this explanation. The differences also do not suggest any other simple error in the measurements. There are several factors that could contribute to what you see in the data. These include: measurement of different samples, degradation of the samples (fading or becoming soiled), differences in the instrumentation (geometry, measured area, accuracy/precision, calibration). I would suspect that these differences are caused by differences in the measurement techniques and instrumentation, particularly in that time period. For example, it is quite likely that the 1933 measurement were completed with a visual instrument (perhaps relative to some arbitrary white) and that the 1940 measurements were completed with an early photo-electric spectrophotometer. (Back to top)


References

  1. G. Wyszecki and W.S. Stiles, Color Science: Concepts and Methods, Quantitative Data and Formulae 2nd Ed., Wiley, New York, 1982.
  2. R.W.G. Hunt, Measuring Colour 3rd Ed., Fountain Press, England, 1998.
  3. R.M. Boynton, Human Color Vision, Special Limited Edition, Optical Society of America, Washington D.C., 1992.
  4. M.D. Fairchild, Color Appearance Models Addison-Wesley, Reading, Massachusetts, 1998.
  5. R.S. Berns, Billmeyer and Saltzmann's Principles of Color Technology, Wiley, New York, NY, 2000. (from Wiley)
  6. H.G. Völz, Industrial Color Testing 2nd Ed., Wiley-VCH, Weinheim Germany, 2001.
  7. There are several links to GretagMacbeth's Color Conversion Freeware